One of the major problems associated with thin dielectrics is defects in the form of micropores or voids in ultrathin SiO2 when oxides are thermally grown from the silicon substrate. This study describes the synthesis of thin multilayer stacked oxides by the sequential growth of thermal oxide layer and the deposition of a layer of LPCVD oxide followed by a densification/reoxidation step (3-step process) to reduce the density of these micropores. The electrical characteristics of these stacked oxides were compared with those of conventional thermal oxide and reoxidized-deposited oxide (2-step process). The stacked oxides formed by the 3-step process exhibit a drastic reduction of the defect density. This improvement is believed to be due to the misalignment and filling up of the micropores in the thermal oxide layer by the deposited oxide layer. Variation of the thickness of the deposited oxide shows that LPCVD oxide of about 30Å in the 3-step process is sufficient in reducing defect density and improving the breakdown characteristics of the stacked oxide. Using this simple stacked oxide process, the yield of ultrathin oxides can be improved significantly.